J.J. Abrams' Star Trek Into Darkness opened to a softer-than-expected $13.5 million at the North American box office on Thursday, putting pressure on the sequel to quickly engage warp speed.

Paramount believes the 3D pic will gross between $90 million and $100 million through Sunday but, based on Thursday results, rival studios were quick to speculate that the sequel may play more in line with Abrams' 2009 reboot, which opened to $79.2 million.

However, Paramount believes Into Darkness will quickly pick up the pace and is anticipating a $20 million-plus Friday.

Trekkies are heartily endorsing Into Darkness, giving it an A CinemaScore. Reviewers also have wholeheartedly embraced the sequel, which returns Chris Pine and Zachary Quinto in the roles of Captain James T. Kirk and Spock. Other returning castmembers include Zoe Saldana, Anton Yelchin, Simon Pegg, John Cho and Karl Urban.

Into Darkness faces tough competition in holdovers Iron Man 3 and The Great Gatsby,

Overseas, Into Darkness opened in seven markets last weekend. The 3D pic has grossed a stellar $37 million through Wednesday, 70 percent ahead of the 2009 film.

Paramount and Skydance co-financed the $190 million tentpole, and produced alongside Abrams' Bad Robot. The script was written by Roberto Orci, Alex Kurtzman and Damon Lindelof.

This time, a scheming villain played by Benedict Cumberbatch resorts to terrorism to threaten Earth.